If the popularity of bridal “boot camps” and shows like Shedding for the Wedding are any indication, losing weight for the wedding day ranks high on women’s lists of pre-nuptial tasks. So much so that the term brideorexia (a reference to the potentially fatal eating disorder anorexia) has entered the lexicon. But are women really taking their bridal diets to that extreme?

It’s true that many brides-to-be try to shed unreasonably large amounts of weight. In a 2000 Cornell study of 273 women who were getting married within the year, 70% of respondents reported wanting to lose more than 20 lb. But in reality, by wedding day, their average weight loss was 7 lb.

“Clearly we live in a culture that values thinness, and this is probably the event of most women’s lives that puts the brightest spotlight on them,” says Dr. Jeffrey Sobal, a co-author of the study and a professor of sociology at Cornell. “But for most, the methods [the women reported] were fairly benign: they did more exercise, increased fruits and vegetables, used weights. My projection is that it really isn’t a problem except in a few extreme cases.”

What about those extremes? Sobal says a minority of women in his study — fewer than 10 — engaged in unhealthy weight-loss behavior like taking laxatives, using liquid diets, smoking to suppress appetite and over-restricting calories. But it’s possible that the changing landscape of the wedding industry has resulted in an increase in extreme cases over the years.

“In the 1990s, there were relatively few entrepreneurial pushes to get women to lose weight. Of all the wedding magazines we could get our hands on, we only found one weight-loss ad,” says Sobal. “That’s changed since 2000. Now there’s bridal boot camp, extreme makeovers, and they encourage bridal weight loss. There’s a little more pressure by profitmaking groups and competition emphasis on thinness in the bridal community.”

Worse, the media continues to celebrate the image of a svelte bride: the British tabloids have been making a fuss over how much Kate Middleton’s 5-ft. 10-in. frame has whittled down since the 29-year-old made her first official appearance as Prince William’s fiancée on Feb. 24. It does appear that Middleton has shrunk from a reported U.K. size 10 (size 6 in the U.S.) to a tiny U.K. size 6 (U.S. size 2), but whether she has developed a case of brideorexia is unclear.

Certainly, if Middleton were suffering from anorexia nervosa — a serious psychological condition that kills 10% to 20% of patients — or some other eating disorder, the media scrutiny of her pre-wedding figure probably wouldn’t be helping. What’s more, it could be a trigger for the 1% of the U.S. population who do have anorexia, according to Dr. Ira M. Sacker, an eating-disorder specialist and associate professor of pediatrics at NYU-Langone Medical Center.

“Numbers are triggers,” says Sacker. “People who are on the verge of an eating disorder are people who are body-image conscious, who might say, ‘If she can do it, I can do it.’ When major figures lose weight, there’s a social copycat effect that’s real.”

And for a minority of brides, a short-term extreme-weight-loss regimen can turn into a chronic problem. According to Sacker, who has seen an escalation in “brideorexic” behavior over the past decade, about 10% of women who start risky pre-wedding diet and exercise programs will develop a lasting disorder. Such women, who are often already predisposed to developing an eating disorder, may be pushed over the edge by the stress of their impending wedding day, Sacker says.

Who’s at risk? Women with a lifelong preoccupation with body image, a perfectionist streak or a previous diagnosis of obsessive-compulsive disorder. Women who have recovered from eating disorders in the past are also at greater risk. Sacker has treated brides who have abused stimulants or laxatives to lose weight, exercised compulsively or developed disordered eating, such as drastically restricting their food intake or eating food in a ritualistic way. Some women may also engage in disordered thinking, becoming preoccupied with a specific body part or obsessively measuring themselves.

What differentiates these behaviors from simple short-term crash dieting — which is also not healthy — is that they can snowball in vulnerable women and result in full-blown chronic illness. Worse, dramatic weight loss and malnutrition can reduce levels of serotonin in the brain, a neurotransmitter that contributes to feelings of happiness and well-being, while increasing levels of other chemicals that increase stress. The result may be depression and social withdrawal, which can trigger a feedback loop of destructive behavior in vulnerable women.

“There’s nothing wrong with losing weight,” says Sacker. “Brides are going to do that. To try and change that is ridiculous. But if it’s an extreme issue — if we’re using restriction, diuretics, stimulants and other risk-taking behavior — they should know there are rebound effects.”

If you’re worried that a friend may be at risk of taking her wedding diet too far, Sacker suggests looking out for certain red flags:

1. Changes in food-related behavior: Does she avoid social situations that involve food? Does she play with her meal instead of eating it? Has she turned eating into a ritual — eating the exact same thing each day or refusing to eat outside of a rigid schedule?

2. Extreme calorie shedding: Is she suddenly exercising more than 30 to 45 minutes a day? Does she run to the bathroom after a meal?

3. Changes in mood: Has she become depressed, irritable, apathetic or agitated?

4. Social isolation: Is your friend withdrawing socially? She may seem more self-involved, introspective and spacey.

5. Extreme weight loss: Abnormal thinness is an obvious sign, as well as fatigue, dizziness or fainting, dry skin and brittle nails.